Firstly, I am not an electrician! But help. I went to put the heating on last night and it won't work. The boiler is controlled by a Honeywell CM921 wireless thermostat that RF links with a BDR91 Relay box. The relay box is constantly showing a flashing red light - RF failure. I have tried to Rebind the thermostat to the box and, although the lights seem to flash as expected - ie both units are poised to link up - the CONTROL BINDING step always fails. I am thinking about buying a new thermostat and relax box but am scared that may not solve it. Any ideas? It is quite a new system (2yrs) and worked fine, but the red light has been on for some time so RF link must've been lost a while ago . its only because I wanted to start using the heating for winter that I've noticed it. Many thanks
5.1 Binding / Rebinding Procedure The binding operation described below is required if: ? Any of the system components (room thermostat or Relay Box) are replaced. ? The Relay Box has incorrect or no binding data stored (e.g. when pre-bound system pack components have been mismatched). NOTE: During the binding procedure keep approximately 1m distance between the room thermostat and the Relay Box. To bind/rebind: 1. Press and hold the Relay Box push button for 15 seconds to reset any previously stored data. After 15 seconds the red LED will change to flashing 0.1sec on/0.9sec off. NOTE: After 5 seconds the red LED will start to flash 0.5sec on/0.5sec off, but continue to hold the button). 2. Release the push button. 3. Press and hold the Relay Box push button for 5 seconds to enter the binding mode. The Red LED will start flashing at 0.5sec on/0.5sec off to confirm the binding mode has been entered. 4. Move the room thermostat slider to the OFF position and press the and buttons together along with the button. The unit will display InSt and ?CONTROL BINDING?. 5. Press the green button to send the binding signal out to the Relay Box. The red LED is switched off to confirm successful binding operation. If the red LED still flashes push the button again until binding is successful. 6. Now go to Section 2) Installing the CM900 Wireless System to setup the system. Are you sure the batteries are ok Mark?
I went through the rebinding procedure as you describe and all the lights on the box plus display on the thermostat seem to do things correctly... its just that at the last step (when pressing green button), it fails to bind. The batteries in the thermostat are quite new, so I don;t think its that. It confused me as I thought it would work but at the last minute failed. I may buy a new set of controller/relay box but it is expensive if it doesn;t fix the problem.
Mark, There is only two reasons this happens, 1. low battery and 2. No RF. You can download a troubleshooter from www.honeywellcontrols.co.uk/downloads and look for your model. If there is a small icon that resembles a battery then the battery is dead if there is a red icon flashing or constant the RF is lost. have you made any alterations to your property since you last used it? is there new furniture in line of site from the thermostat to the relay? sounds silly but if the signal was weak to start with then any change could affect it. If you download the troubleshooter it will show you how to 'override' the RF connection to get the heating working just now while you resolve the RF link.... hope this helps
Hi BrightSpark Tried again last night and it worked! It wasn;t clear in the instructions I had that after holding down relay box button for 15s you then had to hold it again to "re-enter" binding mode. Brilliant, so pleased its sorted. Wife suitably impressed. Thanks for the prompt advice
Hi All, I am experiencing the same issue with my CM927. Can you please help? I got to the following stage but was a little confused... What do you mean by the 'and buttons' and what is the other button you mentioned? 4. Move the room thermostat slider to the OFF position and press the and buttons together along with the button. The unit will display InSt and ?CONTROL BINDING?. Should the display (thermostat) still be in OFF mode? I have tried but with no success, the red light actually goes solid a short while after with the green light flashing, this is without the override function kicking in. Please advise what I am doing wrong, I am most grateful for any advice. Thanks
Just found this info on another website and it worked installation manual wrote: To check the RF communication, hold the room thermostat about 2-3 metres from the installed receiver box. Move the slide to OFF then press the temp up, temp down and right arrow[buttons together for 3 seconds. The unit will display Test Transmitand will send test signals to the receiver box, flashing the green light on every six seconds (the relay will be off so the boiler will not go on and off. Moving the slider to another position will stop the test If the green light is not switched on and off or you get a red light flashing you need to rebind Installation manual wrote: 1. Press and hold button on receiver box for 15 seconds. After 15 secs the red will flash 0.1 secs on/0.9 secs off (Note: after 5 seconds the light will flash 0.5 sec on/0.5 sec off, but continue to hold the button in) 2. Release the button 3. Press the receiver button for 5 seconds until it flashes 0.5 secs on/0.5 secs off. 4. Move the slider to OFF then press the temp up, temp downand left arrow[together. The unit will display InSt and "Control Binding" 5. Press the Green OK button to send a signal to the receiver. The red light should go out. If the red light does not go out, press the OK button until it does. If this does not work one of the components is faulty, or the batteries are dead. Read more: http://www.diynot.com/forums/viewtopic.php?t=129283#ixzz3I7IeZWbK
I had the problem with a Horstmann wireless thermostat, over 6 month it slowly lost range, it could be free standing and to start with it was used that way, however it would fail both ways, some times not turning on the boiler, some times not turning it off. In my case this was a second thermostat so when it failed to switch on the other thermostat in parallel took over, however the other thermostat was in a different room, idea was the times set swapped which thermostat controlled night and day, it ended up with the Horstmann thermostat being placed in the kitchen within one meter of the receiver and other thermostat moved into hall, and electronic TRV heads fitted to control rooms. However it did show me the problems with RF control, even standing between the thermostat and receiver was enough to make it fail, and it did not seem to resend, so once blocked it did not work until room temperature had changed causing it to transmit again. The Honeywell is also wireless but never been a problem, and it has a fail safe, so no received signal in I think an hour it auto closes down. I would suggest putting the putting the thermostat right by the receiver and see if it works then.